A Cabinet show of unity over the Government's controversial health reforms was undermined when the Department of Health declined to confirm that a "listening exercise" would change the plans.

David Cameron, Nick Clegg and the Health Secretary Andrew Lansley joined forces in an attempt to woo health professionals into supporting Mr Lansley's plans to transfer 60 per cent of the NHS budget to GPs. But cracks emerged only an hour after their carefully-choreographed appearance at Frimley Park Hospital in Surrey, where they promised to "pause, listen and reflect" but insisted the status quo is not an option.

Downing Street sources endorsed Mr Clegg's pledge that the rethink would be followed by "substantive changes". Mr Cameron is expected to order Mr Lansley to give councillors a role on the GP-led consortia that will commission services instead of primary care trusts (PCTs)—a key Liberal Democrat demand. More health professionals such as hospital doctors and nurses will be added to the commissioning bodies and limits imposed on competition to allay fears about "back door privatisation."

But Simon Burns, the Health Minister and Mr Lansley's deputy, refused to accept there would be substantive changes, saying there were "misconceptions" and "misrepresentations" about the reforms. "It would be inappropriate of me at the beginning of an independent process... to start saying categorically what we are definitely going to do," he told BBC Radio 4's World at One programme.

Mr Lansley is insisting that the handover to GPs goes ahead in April 2013 as planned. He appeared defensive about watering down his plans but hinted at some changes in four areas: choice and competition; public accountability and patient involvement; education and training to support the modernisation plans and involving different healthcare professions to improve patient care.

The Prime Minister stressed: "We will listen and we will make any necessary changes." Describing himself as "passionate" about the NHS, which he said was Britain's "most precious national asset", and re-called his experience while his family cared for his disabled son Ivan, who died aged six in 2009. "I make no apologies about this but for me this is a very personal thing. I know what it's like to rely on our NHS. I know what it's like to put people you really love in the hands of doctors and nurses and carers in our hospitals," Mr Cameron said. "I know what it's like to turn up in the middle of the night desperately worried and wanting the very best health care free at the point of use from our excellent NHS in Britain." Similar comments after Mr Cameron became Tory leader in 2005 helped to calm voters' fears about his party's commitment to the NHS before last year's general election. Yesterday's remarks showed that Mr Cameron believes they need to be reassured again.

Mr Clegg, who believes the reforms are now back on track, said: "It's right that family doctors are in the driving seat; they know their patients best. But there have to be safeguards. And there will be."

An "NHS Future Forum", led by Steve Field, former chairman of the Royal College of General Practioners, will allow NHS staff to express their views at events around the country.

But Labour and health unions dismissed the "listening exercise" as a PR stunt. Jill Walker, a biomedical scientist who has worked at Frimley Park for 29 years and chairs the staff union body, said after yesterday's event that Mr Cameron had failed to address "the real fears and general unrest" among NHS workers. "It did not reassure me at all that the Government would listen," she said.

A letter-writing and email "Save our NHS" campaign, organised by the Armchair Army, is targeting media outlets and MPs. It claims the Coalition have launched the review because of next month's council elections.